In recent years, various methods have been proposed in fingerprint and palm print recognition. Examples of optical method for recognizing fingerprint and palm print include total reflection method, light-path, separation method, and scanning method. In a total reflection method, light from a light source such as ambient light enters into a pixel, and is totally reflected on the surface of a package substrate. When a finger or palm touches the display panel, the total reflection condition of the surface changes locally upon touch, leading to a disruption of the total reflection locally. The disruption of the total reflection results in a reduced reflection. Based on this principle, the ridge lines of a finger may be differentiated from the valley lines. Alternatively, fingerprint and palm print may be recognized by detecting changes in capacitance when a finger touches the display panel.